NZ707907B2 - A backing plate and wiring housing unit - Google Patents

Abstract

backing plate and wire housing unit for inclusion in an electrical circuit to hold wiring, the unit having a relatively wide front and a relatively narrow back, the back being adapted for location in a channel while the front bridges across the channel. The front includes a planar front face having an opening adapted to be closed by a cover plate, and a surrounding margin having a rearwardly extending flange (41), a rear edge (42) of the flange lying in a plane parallel to the front face. The back extends rearward and being hollow to hold wiring such that the wiring is accessible through the opening. The back includes a wire passage means for passage of wiring into the hollow back for electrical connection of wiring to the cover plate. The back includes a stepped portion (43, 44) which lies either co-planar with the plane occupied by the rear edge or between the plane of the front face and the plane occupied by the rear edge. g an opening adapted to be closed by a cover plate, and a surrounding margin having a rearwardly extending flange (41), a rear edge (42) of the flange lying in a plane parallel to the front face. The back extends rearward and being hollow to hold wiring such that the wiring is accessible through the opening. The back includes a wire passage means for passage of wiring into the hollow back for electrical connection of wiring to the cover plate. The back includes a stepped portion (43, 44) which lies either co-planar with the plane occupied by the rear edge or between the plane of the front face and the plane occupied by the rear edge.

Description

A Backing Plate and Wiring Housing Unit Technical Field THIS INVENTION relates to a backing plate and wiring housing unit for inclusion in an electrical circuit to hold wiring.

Background It is common practice to provide electrical switches and data sockets where wiring is held in a wall cavity behind a backing plate. A cover plate is fastened to the backing plate. The cover plate usually carries a switch, power plug socket or data socket or combinations of these. The backing plate may be in the form of a metal bracket which fits inside the wall cavity behind wall cladding having been nailed or otherwise secured to a vertical stud. An opening is made in the cladding to enable access to the bracket. The metal bracket has spaced threaded holes to receive screws that hold the cover plate. In this case the cover plate is larger than the opening in the cladding so that the cover plate is secured hard against a margin around the opening in the cladding. In another form the backing plate may be part of a plastics box form. The box form is rectangular and has front and back openings so that as an option wires may enter from the back and a cover plate may be fitted to the front. It has frangible wall sections that may be broken away for side entry of electrical conduit. It is often secured to a surface so that the back opening is closed by the surface and the box receives conduit carrying wiring and holds the wiring ends within the box. In this case the cover plate is secured to the box after the wiring has been fitted off to the cover plate.

The cover plates are standardised as to size and screw spacing so that they may be used in both situations and power points, light switches and data cover plates of particular manufacturers are all interchangeable. Where there is no wall cavity to carry the wiring, the electrician usually builds a timber improvised arrangement where the plastics box is secured to the timber and wiring passes through holes drilled in the timber to an insulated position within the box. This prior art has been used for many years, at least 20 years and there has not been any newly developed backing plate or wiring housing that has entered the market or became well known or in common use.

The present inventors have recognised, as far as applicant knows, for the first time the need to provide for the wiring of a cover plate as an alternative to the improvised timber arrangement in circumstances involving external metal cladding as in sheds, garages and the like although the present invention is not limited to use in these environments. The present invention provides a solution to the problem of the insulation of connections to cover plates where there is no wall cavity and eliminates the need for an improvised arrangement for fixing the backing plate.

Summary of the Invention In accordance with the present invention, there is provided a backing plate and wire housing unit for inclusion in an electrical circuit to hold wiring, the unit having a relatively wide front and a relatively narrow back, the back being adapted for location in a channel while the front bridges across the channel, the front includes a planar front face having an opening adapted to be closed by a cover plate, the back extending rearward and being hollow to hold wiring such that the wiring is accessible through the opening, the back includes a wire passage means for passage of wiring into the hollow back for electrical connection of wiring to the cover plate, wherein the back further includes a stepped portion having a matching and complementary inner step so that the front has a wide opening stepping down inside to a tapered back portion offset from the front. [0004a] The stepped portion preferably lies either co-planar with the plane occupied by the rear edge or between the plane of the front face and the plane occupied by the rear edge. Typically, the back is adapted for location in a recess such as a channel with the front bridging across the channel. The unit is typically moulded from plastics of the same kind conventionally used for plastics backing plates of the box type but any suitable plastics may be used. Typically, the unit has a wide to narrow aspect front to back.

Typically, the front is configured to match standard cover plates used in power points, light switches, data sockets and as blank cover plates. The unit has spaced screw holes matched for this purpose and formed in usual way. These standard cover plates are only examples, the present invention could be utilised with any cover plate.

Preferably, the front has mounting means so that the unit may be secured in place in the opening or channel. This would usually prevent any axial or lateral movement relative to the channel. Typically, the front has a tab, flange or other projection to provide for a screw or fastener to fasten the front to a support surface near to the channel. In a preferred form the unit has a flange or flanges for this purpose. Where there is a flange, the flange is typically a lateral flange or bilateral flanges are used. In another embodiment there is a flange surrounding the front defining an opening into the hollow unit. This flange is a marginal peripheral flange.

The back has an outside including top, bottom and opposite sides with the top and bottom typically generally matched to a channel in terms of general shape but it is only necessary that the back be narrow relative to the front and have a hollow within it sufficient for wiring purposes. This means that it is not a requirement that the outside of the back be any particular shape other than that it fits in the space and be relatively of reduced size compared to the front. Preferably, the back should extend rearward enough so that a conduit located in the bottom of the channel might easily line up and run into the passage means to the unit. Generally speaking, the back has a general taper in depth in the top and bottom with a constant width although there could be a side taper as well. The taper can be substantially symmetrical top and bottom but need not be. In the most preferred from the back fits snugly in the channel.

The front has a front planar face which may include a surrounding margin with a rearward flange with a rear edge parallel to the front face and the back has a stepped portion located between the plane of the front face and the plane occupied by the rear edge level of the rear edge of the flange or co-planar with it. In other words the rear edge will mount flush when the step is stopped by the channel surround. So as to ensure flush mounting, the edge could be marginally further back than the stepped portion. This stepped portion has a matching and complementary inner step so that the front has a wide mouth stepping down inside to a tapered back portion offset from the front by the depth of the flange. This gives wider access to the interior to facilitate wiring fitting off in the case of narrow channels.

The passage means typically comprises "knock outs" on opposed sides so that conduits may fit in line on opposite sides which conduits each run cables along the channel inside the conduits. Typically, three knock outs are provided to enable the formation of a "T" junction at the unit with passage means at both sides and the rear of the unit. In another embodiment the passage means may comprise a tube section or axially extending conduit collar projecting from the back. The collar may have internal knock outs. There may be a collar at each side of the unit such that the collars are axially spaced along the channel. The collars may be partially inside and partially outside the unit. Typically, the collars take conduit as a push fit.

The channel is typically a horizontal batten extending between posts or studs and used between and to secure wall panels to the posts or studs in a wall.

In this embodiment the channel is a long folded or extruded metal rail with flanges on either side of the channel and these flanges are used to secure the front of the unit with screws.

As a consequence of the invention there is also described the combination of a backing plate and wiring housing mounted in a channel, the housing having a wide to narrow aspect front to back, the wide front extending across the channel with the back in the channel. As an example of this and in one preferred application the invention comprises in a metal shed wall construction having wall panels, spaced posts and a horizontal batten securing the wall panels to the posts, the batten having a channel profile with vertical flanges extending on either side of the channel, a conduit carrying electrical wiring in the conduit and extending along the channel, a backing plate and wire housing unit connected to the conduit, the unit having a front and a back, the front being secured to the vertical flange of the batten, the back being located in the channel of the batten, the front being closed by a removable cover plate, the back extending rearward and being hollow and holding wiring coming from the conduit and being connected to the cover plate.

There is also described a mould for forming a hollow injection moulded backing plate and wire housing unit, the hollow injection moulded backing plate and wire housing unit having a rear section with an inside wall and an outside wall, the mould having a first mould section(s) and a second mould section(s), the first mould section(s) having a tapered projection substantially a positive of the inside wall of the back section of the unit and the second mould section(s) having a cavity substantially a negative of the outside wall of the rear section of the unit, the first mould section(s) having bilateral conduit collar forming recesses and the second mould section(s) having conduit collar forming recesses, the recesses being substantially co-axial with part of the collar inside the moulded unit and part outside the moulded unit.

Brief Description of the Drawings In order that the present invention may be more readily understood and be put into practical effect the present invention will now be described with reference to the accompanying drawings which illustrate preferred embodiments and wherein: Figure 1 is a drawing of part of a shed construction where a wall construction according to an embodiment of the present invention is used; Figure 2 is a drawing similar to Figure 1 showing a close-up of a preferred backing plate and wire housing unit in accordance with an embodiment without the wiring or cover plate in place installed in a typical wall construction; Figure 3 is an exploded view illustrating the assembly of a typical backing plate and wire housing unit in accordance with an embodiment which may be used with a cover plate being a double power point; Figure 4 is a drawing illustrating the arrangement of Figure 3 in its assembled form; Figures 5 are orthographic and perspective drawings of a preferred backing plate and wire housing unit according to an embodiment of the present invention; Figures 6 -7 illustrate a preferred embodiment of the present invention.

Description of Embodiments Referring to the drawings and initially to Figure 1 there is illustrated part of a shed 10 having columns 11 and 12 and horizontal girts or battens 13 and 14, with the batten 13 being situated at the usual height at which light switches or power points may be desirable in this case, the batten being used to secure wall cladding 15 to the columns 11 and 12 via the battens 13 and 14.

The batten 13 has backing plate and wire housing units 16 located in the batten13 and secured in place where power points may be desirable, where after a length of conduit along the batten 13 is used to carry wiring to the power points as will be described in greater detail in relation to the following drawings. The batten 14 could carry wiring if floor level outlets were desirable.

Figure 2 illustrates a close-up view of the second backing plate and wire housing unit 16 with conduits 17 and 18 extending from the backing plate and wire housing unit 16. It will be understood that the conduit extends the full length of wiring although part only is shown in the figures. The batten 13 has a cross- section as illustrated in Figure 1 and in Figure 3. The backing plate and wire housing unit has a peripheral flange 19 which enables the backing plate to be secured to the flanges 20 and 21 of the batten 13 using four screws 22. In the illustrated embodiment of Figure 3 a double power point cover plate 23 of standard design is secured using screws 24 while a clip on surround 25 finishes the assembly. This of course is completed after the power point is wired up. The final assembly is shown in Figure 4.

Figures 5 show the various orthographic views of the typical unit along with front and rear perspectives. There are four fixing holes 25, a rear wall 26 and tapered top and side walls 27, 28, 29 and 30 of the back. Integral conduit collars 31 and 32 are formed in the sides so that the collars are just forward of the rear wall 26. The collars are a push fit onto conduit. The cover plates are secured using self tapping screws which locate in the screw receivers 33, 34 35, 36. There are four of these so that the unit can fit the two standards currently available so only two of these would be used as shown in Figure 4.

Figures 6-8 illustrate a further embodiment 37 in this case the unit differs in so far as it has a revised front configuration 38 but the rear is still substantially the same and the two units are interchangeable in so far as the channel they fit. The front has a surrounding margin 40 with a rearward flange 41. The edge 42 of the flange 41 is at the same level as an outer shoulders or steps 43 and 44. The shoulders 43 and 44 have matching internal shoulders or steps 45 and 46. The result of having this flange 41 and the shoulders is that the unit is set out by the width of the flange so that the opening provided by the perimeter 47 is widened and extra clearance is available for a wider range of internal fittings on the cover plate. The outer shoulders also provide an extra seat for greater stability. Fitting slots 48, 49, 50, 51 enable fitting with screw fasteners and the holes 52, 53 and screw receivers 54, 55 are matched to the standard cover plates. Conduits can be attached as in the previous embodiment.

Whilst the above has been given by way of illustrative example of the present invention many variations and modifications will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as herein set forth. For example, the invention could be used in any application where a channel is involved to carry wiring.

Claims (11)

CLAIMS 1.:

1. A backing plate and wire housing unit for inclusion in an electrical circuit to hold wiring, the unit having a relatively wide front and a relatively narrow back, the back being adapted for location in a channel while the front bridges across the channel, the front includes a planar front face having an opening adapted to be closed by a cover plate, the back extending rearward and being hollow to hold wiring such that the wiring is accessible through the opening, the back includes a wire passage means for passage of wiring into the hollow back for electrical connection of wiring to the cover plate, wherein the back further includes a stepped portion having a matching and complementary inner step so that the front has a wide opening stepping down inside to a tapered back portion offset from the front.

2. A backing plate and wire housing unit according to claim 1 wherein the front portion further includes a surrounding margin having a rearwardly extending flange, a rear edge of the flange lying in a plane parallel to the front face.

3. A backing plate and wire housing unit according to claim 2 wherein the stepped portion lies either co-planar with the plane occupied by the rear edge or between the plane of the front face and the plane occupied by the rear edge.

4. A backing plate and wire housing unit according to any one of the preceding claims wherein the front is configured to match standard cover plates used in power points, light switches, data sockets and as blank cover plates.

5. A backing plate and wire housing unit according to any one of the preceding claims wherein the front has mounting means so that the unit may be secured in place, the mounting means including a plurality of fitting slots to provide for a screw or fastener to fasten the front to a flange of the channel.

6. A backing plate and wire housing unit according to claim 5 wherein the mounting means is provided in the surrounding margin of the front face.

7. A backing plate and wire housing unit according to any one of the preceding claims wherein the wire passage means includes "knock outs" on opposed sides of the back so that conduits may fit in line on opposite sides, said conduits run along the channel and house inside the electrical wiring.

8. A backing plate and wire housing unit according to any one of claims 1-6 wherein the wire passage means includes a tube section or axially extending conduit collar projecting from the back.

9. A backing plate and wire housing unit according to any one of claims 1-6 wherein the wire passage means includes a tube section or axially extending conduit collar projecting from each side of the back such that the collars are axially spaced along the channel.

10. A metal wall construction having wall panels, spaced posts and a horizontal batten securing the wall panels to the posts, the batten having a channel profile with vertical flanges extending on either side, a conduit extending along the channel of the batten and carrying electrical wiring within, the construction further including a backing plate and wire housing unit as claimed in any one of the preceding claims connected to the conduit, the back being located in the channel, the back holding electrical wiring coming from the conduit, and being connected to the cover plate.

11. A backing plate and wire housing unit substantially as hereinbefore described with reference to